Eight people died at the scene of the shooting at Twin Peaks restaurant in Waco about noon and another person died later at a hospital, local media reported.

The fighting began with punches and then escalated to knives and firearms. The fight broke out inside the restaurant before moving to the parking lot. It escalated from fists and feet, to chains, knives and gunfire, police said.

It's not immediately clear if bystanders are among the dead, Waco police Sgt W Patrick Swanton was quoted as saying by media. All of the victims were gang members. Several other bikers were injured. The severity of the other injuries was not immediately clear, police said.

Swanton said police were aware that gang members were gathering at the restaurant and officers were present when shots began. Some of the officers fired on bikers as the shooting spilled from the restaurant into a busy parking lot. Patrons and bystanders dove for cover.

"There was an incident but thankfully the awesome Waco Police have been on the premises and assisting with this situation. We will share more details as we find out ourselves on what's going on. Thank you. All of its employees and customers are safe," a Facebook post by the restaurant staff said.

The restaurant is in a shopping centre called the Central Texas Market Place.